"Tom Coates" wrote in message
...
Thanks, everyone, for the insights. I think I'll get it working without
the
pulsing and then reconsider.

It appears that what was described to me as a standard technique is much
more experimental.

Tom, N3IJ

"Tom Coates" wrote in message
...
I want to build some emergency lighting equipment using LEDs and 12V. A
friend told me that it is possible to get more light per Watt by pulsing
the LED to instantaneous levels well above its average ratings.

Is this true, if you include power consumed in the pulsing circuit?
Tom, N3IJ


Good luck...However. I did find one Agilent ap note about LEDs , but it
didn't mention pulsed vs. non-pulsed brightness...much.

I did build a pulsed LED driver a long time ago. It used an inductor and
comparator. Turn on switch in series with LED, inductor ( tried 1mH first )
and supply. When current ramps up to the desired, turn off switch. A
"catch" or "fly-wheel" diode then conducts current through LED & inductor
while current decays to a lower level where switch turns on. Neat to see
the supply current less than the LED current.

73, Steve, K9DCI

On Wed, 12 Oct 2005 19:28:03 -0400, "Tom Coates"
wrote:

I want to build some emergency lighting equipment using LEDs and 12V. A
friend told me that it is possible to get more light per Watt by pulsing the
LED to instantaneous levels well above its average ratings.

Is this true, if you include power consumed in the pulsing circuit?

If it is, can anyone suggest a simple and cheap circuit and the appropriate
operating values?

The reason for the 12V requirement is that I'm also working on a solar
charger for my transceiver batteries and want to use the same charger for
the lighting batteries.

Suggestions would be appreciated.

Tom, N3IJ


take a look at the new crop of 1W LED flashlights that are on the
market. A lot of very white light from these modules. No need to
bother with trying t get intensity, something like 8 hours off 3 AAA
batteries.